Ear Anatomy, Histology, And Vestibular And Auditory Pathways

Front 1

what seperates the outer ear from the middle ear?

Back 1

tympanic membrane

Front 2

Parts of the auricle:

Back 2

helix, antihelix, lobule, tragus, antitragus

Front 3

What process of the incus articulates with the stapes?

Back 3

The lenticular process on the edge of the long crus of the incus

Front 4

What space surrounds the ossicles?

Back 4

Epitympanic recess

Front 5

What does the bone surrounding the epitympanic recess contain?

Back 5

The mastoid air cells

Front 6

Otitis media is what? How do these infections usually occur?

Back 6

Infection of the middle ear. The pharyngeal tonsil is at the base of the Eustachian tube which leads directly to the middle ear.

Front 7

What is contained in the middle ear?

Back 7

ossicles, Eustachian tube, and the epitympanic recess

Front 8

Describe the significance of the size difference between the tympanic membrane and the footplate of the stapes?

Back 8

Tympanic membrane is bigger by a ratio of 10:1, this allows for better mechanical detection of sound.

Front 9

The cochlea is used for what? Contains what necessary structures? Is located where?

Back 9

Used for hearing, contains the organ of corti, and located in the inner ear in the petrous portion of the temporal bone

Front 10

What is the route of the facial nerve in relation to the ear structures?

Back 10

Travels through the internal auditory meatus with CN VIII near to the inner and middle ear structures and out the stylomastoid foramen.

Front 11

What is the relationship of the internal carotid with the eustacian tube? The internal jugular vein?

Back 11

Posterior to the Eustachian tube, anterio-lateral to the Eustachian tube

Front 12

In what direction does the external auditory meatus travel?

Back 12

Medially, anteriorly, and inferiorly

Front 13

what is the positioning of the tympanic membrane?

Back 13

The superior portion tilts laterally to the inferior portion

Front 14

Where do the tympanic membrane and the malleus connect?

Back 14

At the umbo

Front 15

What is the role of the tensor tympani?

Back 15

It attaches to the malleus and causes the tympanic membrane to tighten as well so it conducts at lower frequencies so it will not break.

Front 16

The pyramidal eminence in the middle ear contains what structure that attaches where? Which wall of the middle ear does it emerge from?

Back 16

The tendon of the stapedius muscle which attaches to the stapes. The posterior wall

Front 17

The processus cochleariformis in the middle ear gives rise to what structure? Which aspect of the middle ear does it emerge from?

Back 17

The tendon of the tensor tympani. The anterior wall

Front 18

What is the relative positioning of the chorda tympani in the middle ear?

Back 18

Enters the middle ear through the posterior iter and travels lateral to the incus and then medial to the malleus to exit through the anterior iter to the petrotympanic fissue. It is superior to the tendons of the stapedius and tensor tympani throughout its course.

Front 19

What fibers does the chorda tympani convey? From where? What nerve does it join ?

Back 19

SVA for taste and preganglionic parasympathetics for the submandibular ganglion from the facial nerve and it will join the lingual nerve.

Front 20

Which process of the malleus contains the umbo?

Back 20

The lateral process

Front 21

What fact about the ossicles is a contributing factor to elderly hearing problems?

Back 21

The synovial joint between the incus and the malleous can develop arthritis

Front 22

What causes the anterior and posterior malleolar folds in the tympanic membrane?

Back 22

The chorda tympani

Front 23

1. posterior malleolar fold
2. maunbrium
3. umbo
4. cone of light
5. pars tensa
6. anterior malleolar fold
7. pars flaccida

Back 23

label

Front 24

describe the pathway of the of the GVE's to the parotid gland.

Back 24

inferior salvatory nu in the medulla to the glossopharyngeal nerve, through the tympanic plexus to the lesser petrosal to the otic ganglion. The post ganglionics join the auricular temporal branch of the mandibular nerve (V) to innervate the parotid

Front 25

what is the positional relationship to the eustachian tube and the tensor tympani?

Back 25

the tensor is just superior to the eustachian tube

Front 26

what are the three prominences/promotories that are on the wall of the middle ear?

Back 26

the semicircular prominence, facial prominence, and the cochlear promontory

Front 27

where in the middle ear can you see fibers of the tympanic plexus? what nerves make up the plexus?

Back 27

on the cochlear prominence of the medial wall, note they are in the inner ear but can see their indentations. VII and IX.

Front 28

where does the foot plate of the stapes attach?

Back 28

at the fossa ovalis (wall connected to vestibuli)

Front 29

what and where are the two turns of the facial nerve, and what is significant about the more distal one?

Back 29

The internal genu (1st turn) is the loop around the abducens nucleus in the pons. The external genu is posterior to the inner ear so the facial can exit through the stylomastoid foramen. At this point is the geniculate ganglion where the SVA fibers for taste synapse.

Front 30

What nerve does the geniculate ganglion give rise to?

Back 30

the greater petrosal

Front 31

what are the three semcircular ducts in the vestibular apparatus? How are they oriented? Flow of fluid in the ducts will be the same in which ducts during a head movement?

Back 31

the anterior, posterior, and horizontal semicircular ducts. They are all ninety degrees apart. The anterior duct of the right ear and the posterior duct of the left ear will have the same movement of fluid (as well as the opposite situation)

Front 32

what is the difference between semicircular ducts and canals?

Back 32

the ducts are within the BONY canals. The canals contain perilymph while the ducts contain endolymph.

Front 33

what is the large canal in the middle of the bony part of the cochlea? What structures are contained within?

Back 33

the vestibule. It contains the ampulla of the semicircullar ducts as well as two seperate strucutures, the saccule and utricle

Front 34

what inner ear structure does the stapes affect?

Back 34

the perilymph in the cochlea creating a wave like effect

Front 35

what glands produce earwax?

Back 35

the ceruminous glands

Front 36

what epi is found on the internal and external tympanic membrane?

Back 36

internal is simple cuboidal while the external is stratified squamous (continuous with skin in external auditory meatus)

Front 37

where is the elastic layer in the tympanic membrane?

Back 37

in the pars tensa between the two epi layers of the tympanic membrane.

Front 38

what type of epi is found in the eustachian tube?

Back 38

pseudostratified ciliated epi AKA respiratory epi.

Front 39

what are the parts of the bony labyrinth? membranous labyrinth?

Back 39

semicircular canals, vestibule, bony cochlea. semicircular ducts, ampulla, utricle, cochlear duct (AKA scala media)

Front 40

what is the receptor organ for movement found in the saccule and the utricle? what is the basic mechanism and anatomy of its sensation (specefics asked later)?

Back 40

the macula. On top of the CT of the saccule is a layer of cells that contain cilia which intrude into the gelatinous layer of the otolithic membrane; the otoconia (otoliths) is the layer of the otolithic membrane on top of the genatinous layer. The jello layer moves like jello when the head moves, detecting acceleration and change in direction, but not traveling at constant velocity. The vestibular part of the vestibulocochlear nerve detects these movements. Note there are horizontal and vertical maculae for detecting horizontal and vertical movement

Front 41

what are the to different types of cilia in the macula and how do they affect sensation transmission?

Back 41

the kinocilium is the tallest of the cilia while the stereocilium is the shorter. When the stereocilia bend towards the kinocilium, AP firing rate increases while if they bend away from it, AP frequency decreases thus adding directionality to the system.

Front 42

what is the special receptor found in the ampulla? general strucutre of it? how do they detect sensation?

Back 42

the crista ampularis. Group of hair cells with prominent stereocilia with a dome shaped gelatinous membrane over the hairs called the cupula. The three semicircular canals are arranged for 3D detection of movement. As fluid flows through them, it pushes these stereocilia in the ampulla in the opposite direction of the flow due to motion. Since these guys are circular, when you spin around and around, the fluid will keep spinning when you stop, thus you get off balance.

Front 43

what are the three tubes/layers of the cochlea? What is their orientation?

Back 43

scala vestibule (upper), scala media (middle-surrounded by membrane, it is also known as the cochlear duct), and scala tympani (lower).

Front 44

what is the cochlear apex called (where the scala vestibuli and the scala tympani meet)?

Back 44

the helicotrema

Front 45

what are the multiple ganglia in the cochlea called? what kind of fibers do they contain?

Back 45

spiral ganglia. SSA's for hearing.

Front 46

where is the organ of corti located and what is its general anatomy?

Back 46

in the cochlea. It is located on the distal end of the bony plate (spiral lamina) that divides scala tympani and vestibuli. It consists of a basilar membrane that contains hair cells with cilia that rise into the gelatinous tectorial membrane.

Front 47

where is the basilar membrane of the organ of tympani thicker? thinner?

Back 47

towards the helicotrema it is thicker, toward the origin of the cochlea it is narrower

Front 48

what secretes endolymph?

Back 48

the blood vessel in the stria vascularis which is located in the scala media

Front 49

what cells support the hair cells in the organ of corti?

Back 49

phalangeal cells (AKA deiters cells)

Front 50

what is the spiral limbus?

Back 50

connective tissue that supports the distal parts of the basilar membrane of the organ of corti

Front 51

the tickness differences of the basilar membrane of the organ of corti result in what?

Back 51

a tonotopic organization, a secttion of the cochlea responds to specefic frequency sound wave produced by the oscilating ossicles...

Front 52

How many turns are in the cochlea?

Back 52

2.5

Front 53

What is the range of human hearing?

Back 53

20 KHz in the basal end of the cochlea to 20 Hz at the helicotrema.

Front 54

Where is the primary auditory cortex? How is it organized?

Back 54

The transverse temporal gyri of Heschel. It is organized tonotopically, higher pitched sounds are deep in the temporal lobe near the insula while lower sounds are closer to the surface of the lobe.

Front 55

What do you hear in the primary auditory cortex?

Back 55

Frequency (pitch), volume, direction, and timbre (difference between a trumpet sound and piano, e.g.). NO words (need secondary association area like Wernicke’s for words)

Front 56

Why is parallel processing nescecary in the auditory pathway?

Back 56

Some vibration frequencies are faster than the conduction frequencies of the nerve, thus you need more than one pathway.

Front 57

what are the paths of the auditory tracts?

Back 57

nuf said

Front 58

How is the auditory system connected to the visual system?

Back 58

Collaterals from the brachium of the inferior colliculi travel to the superior colliculi for reflex movement of eyes toward a sound.

Front 59

The input of the auditory pathways into the reticular formation serves what purpose?

Back 59

To stimulate a sympathetic effect.

Front 60

What percentage of fibers end up on the ipsilateral side? Clinical significance?

Back 60

20 to 30%. Pts who damage the tract will not experience complete deafness in one ear, but a diminished hearing will occur.

Front 61

What is the olivocochlear bundle and what is its purpose?

Back 61

Feedback to the vestibulocochlear nerve (through superior olivary nu) and thus to the hair cells in the cochlea from the superior colliculus that exhibits a special somatic efferent functional component. It changes the threshold of hair cells to be more sensitive to low amplitude sounds so that things can be “tuned out.”

Front 62

What is the only nucleus of the auditory pathway that does not have communication from one side to another?

Back 62

The medial geniculate body

Front 63

What does Rinnes’ test test?

Back 63

Air conduction vs. bone conduction. Normally air conduction is much better than bone conduction. But if something like otitis media is occurring, the middle ear cavity is full of fluid, thus bone conduction would be better. Arthritic changes in the ossicles would show bone conduction is better as well. If nerve damage had occurred, the pt. would not hear either.

Front 64

What does Weber’s test test?

Back 64

Tuning fork to the middle of the forehead should result in bone conduction and air conduction. Bone conduction would be increased on the side that is infected.

Front 65

The crista ampularis detects what? Macula?

Back 65

Movement from side to side. Inertia.

Front 66

How does the vestibular system travel to consciousness?

Back 66

It does not, it is only a reflex.

Front 67

How many vestibular nuclei are there and what are their names?

Back 67

4 pairs… superior, medial, lateral, and inferior (spinal)

Front 68

How do fibers get to the vestibular ganglia from the ear?

Back 68

Bipolar neurons with bodies in the vestibular ganglia that travel to all 4 of the vestibular nuclei.

Front 69

Where in the cerebellum do the vestibular fibers travel?

Back 69

To the flocconodular lobe

Front 70

what type of neurons are found in the vestibular ganglia?

Back 70

bipolar neurons

Front 71

where in the vestibular tract do cerebellar structures get input and what are the cerebellar parts that get input?

Back 71

from the bipolar neurons from the vestibular ganglia (note this is before they synapse on the vestibular nuclei). These fibers go to the flocculonodular lobe

Front 72

The vestibulospinal tract originates where? travels in what direction? utilizes what tract?

Back 72

in the superior and medial vestibular nuclei, fibers then travel ipsi or contralaterally to the MLF to ascend.

Front 73

where does the medial vestibulospinal tract originate? where does it travel? what does it do?

Back 73

from the medial, lateral and inferior vestibular nuclei to the ipsi and contralateral MLF oand travels down mainly to upper cord levels to change tone in arms, shoulders and other antigravity muscles.

Front 74

the lateral vestibulospinal tract originates where? travels where? does what?

Back 74

from the lateral vestibular nucleus down the ipsilateral lateral vestibulospinal tract which is in the anterior fasciculus of the cord to inhibit the flexors of the arm and to excite the extensors in the leg

Front 75

if the head is moved to the left, in terms of eye movement, what nuclei will be stimulated first? next step?

Back 75

the left superior and left medial vestibular nuclei then to the contralateral lateral gaze center thus your eyes will go right.

Front 76

explain what happens when cold water is put in the right ear? hot water? what is this test called and what does it test for?

Back 76

eyes slowly drift to the right and then snap back to the left thus a left nystagmus. hot water causes a right nystagmus. This is called the COWS test (calloric testing for vestibular function).